MLTX Stock Jumps Over 10% Overnight As Spine Drug Trial Win Sets Stage For Investor Day Showdown

Investors are now turning to Monday’s Investor Day for regulatory clarity, pipeline updates, and key 2026 catalysts.

• Phase 2 S-OLARIS trial data showed 81% of patients improved within 12 weeks, meeting the primary endpoint.
• Imaging and biomarker results confirming reduced spine inflammation, while no new safety issues were identified.
• MoonLake enters Investor Day with funding in place into the second half of 2027, supported by $394 million in cash.

Shares of MoonLake Immunotherapeutics, Inc. (MLTX) surged over 10% in overnight trading on Sunday ahead of Monday’s Investor Day, as newly released clinical data for its experimental spine disease drug reignited investor interest after a volatile year marked by a major setback.

MLTX stock jumped over 3% on Friday to hit $18.77, but ended 0.3% lower in after-hours trading. 

Phase 2 Trial In Spine Disease Meets Primary Endpoint 

On Sunday, the company reported positive topline results from a Phase 2 clinical trial of Sonelokimab (SLK) in patients with axial spondyloarthritis, a chronic inflammatory disease that causes severe back pain, stiffness, and progressive loss of mobility. 

MoonLake said its Phase 2 S-OLARIS trial showed that 81% of patients treated with SLK saw clear improvement in their condition within 12 weeks. The trial met its primary endpoint, using the same standard doctors and regulators rely on to judge whether new treatments for this disease reduce pain, inflammation, and limits on daily movement.

MoonLake reported that more than 80% of patients also showed clinically important improvement on additional disease activity measures by Week 12. These clinical gains were supported by imaging results, with MRI scans showing reductions in inflammation inside affected joints.

PET imaging further showed a reduction in both inflammation and osteoblast activity within the sacroiliac joints by Week 12. Osteoblast activity is a key driver of irreversible bone formation and progressive loss of mobility in axial spondyloarthritis. Tests on patients’ blood and tissue showed that the drug quickly and consistently reduced the inflammation signals that drive the disease to worsen over time.

The company said the safety profile of SLK in the S-OLARIS trial was consistent with previous studies and that no new safety signals were identified. 

Cash Position Extends Runway Into 2027

MoonLake reported that it ended 2025 with $394 million in cash, cash equivalents, and short-term marketable securities. The company said this, combined with proceeds from a recent $75 million equity raise, is expected to fund operations into the second half of 2027.

The company also announced an amended debt facility with Hercules Capital, including a $25 million drawdown and up to $400 million in additional non-dilutive funding available to support future needs.

Why The Data Matters 

The Phase 2 readout marks a positive development for MoonLake following a sharp selloff in September 2025, when one of its Phase 3 trials in a separate skin disease indication failed to meet its primary endpoint. That result triggered a roughly 90% collapse in the stock price over two sessions and sparked a securities class-action lawsuit filed in December.

MoonLake will host its Investor Day on Feb. 23, with presentations from its CEO, chief scientific officer, and CFO, followed by an open Q&A session. The company will also discuss the outcomes of its recent Type B meeting with the U.S. Food and Drug Administration (FDA) regarding hidradenitis suppurativa, including next steps related to label strategy and the planned biologics license application submission. 

Additionally, the company plans to share an interim analysis of the continued response to SLK beyond Week 16 from the Phase 3 Vela trials in adult patients with hidradenitis suppurativa, as well as interim data from the Vela-Teen Phase 3 trial in adolescent patients.

MoonLake said the Investor Day will also include an update on its financial position and a review of key 2026 catalysts. These include upcoming data releases from the Phase 3 Izar trials in psoriatic arthritis, as well as the planned Phase 3 development program in palmoplantar pustulosis.

How Did Stocktwits Users React?

On Stocktwits, retail sentiment for MLTX was ‘extremely bullish’ amid ‘extremely high’ message volume.

One user said, “I didn't think were were getting the financials until Wednesday.   Looks very positive to me.  Tomorrow should be epic, shorts might wanna cover ASAP.”

Another user said, “Today had amazing news, tomorrow morning will have many announcements but there are many more to follow. This is like top 10 roadmaps for any drug company right now” 

MLTX stock has risen 42% year-to-date.

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